tools/gn: Convert for loops to use the new range-based loops in C++11.

tools/gn/pattern.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/pattern.h"
 
 #include "tools/gn/value.h"
 
 namespace {
 
@@ skipping 149 matching lines @@
 
 void PatternList::SetFromValue(const Value& v, Err* err) {
   patterns_.clear();
 
   if (v.type() != Value::LIST) {
     *err = Err(v.origin(), "This value must be a list.");
     return;
   }
 
   const std::vector<Value>& list = v.list_value();
-  for (size_t i = 0; i < list.size(); i++) {
-    if (!list[i].VerifyTypeIs(Value::STRING, err))
+  for (const auto& elem : list) {
+    if (!elem.VerifyTypeIs(Value::STRING, err))
       return;
-    patterns_.push_back(Pattern(list[i].string_value()));
+    patterns_.push_back(Pattern(elem.string_value()));
   }
 }
 
 bool PatternList::MatchesString(const std::string& s) const {
-  for (size_t i = 0; i < patterns_.size(); i++) {
-    if (patterns_[i].MatchesString(s))
+  for (const auto& pattern: patterns_) {
+    if (pattern.MatchesString(s))
       return true;
   }
   return false;
 }
 
 bool PatternList::MatchesValue(const Value& v) const {
   if (v.type() == Value::STRING)
     return MatchesString(v.string_value());
   return false;
 }